The present invention relates to an apparatus for mounting a disk on a shaft, and more particularly to such an apparatus wherein the mounting is effected by axially slidable rings having conical surfaces which produce a radial pressure between the shaft and an inner opening on the disk.
A disk mount of this type is generally known from the company pamphlet "Designing with BIKON Technology," 1979 edition, page 34. In the known configuration, the disk is the bottom of a conveyor drive drum for the belt of a belt conveyor, such as the type used, for example, in surface mining of brown coal. Belt drive drums of this kind may have a length of 2 to 3 m, depending on the width of the conveyor belts. They transmit forces up to approximately 1500 kW to the conveyor belt by friction only. Correspondingly, the tension in the conveyor belt is substantial. The belt drive drums have continuous shafts, which may have diameters of up to 500 mm and are bearingly supported at positions spaced axially outside of the belt drive drum. In spite of the large dimensions of the shaft, a certain amount of sagging still occurs. This sagging is transmitted through a conical tightening mechanism to a flanged ring of the hub. The bolts connecting the hub with the bottom of the drum are exposed to the shear stresses resulting from the transmission of the torque during revolution of the drum as well as to the superposition of tensile stress peaks originating in the sag of the shaft. The tensile strength peaks alternate during drum rotation. This alternating fatigue stressing may lead to the fracture of the bolts.
In the embodiments shown in DE-OS No. 28 01 446, there is no separate flanged hub ring, but the drum bottom is thickened in the area where it joins the shaft. This, however, involves a significant increase in the cost of the drum bottom, the bottom must be milled from a solid body with the removal of a large amount of material in the form of chips, or else expensively cast or forged. The fabrication of the drum bottom from plate material is preferable. In another embodiment shown in DE-OS No. 28 01 446, a flanged hub ring is welded to the drum bottom. The same torque related stresses act on the weld joint as on the axial bolts of the aforementioned embodiment. Otherwise, however, the problem is not as pressing in the configuration discussed above since a tubular, rather than a solid shaft, is used. The tubular shaft has a relatively large diameter which is correspondingly rigid in bending, so that problems resulting from rotating bending fatigue exposures are reduced.